This is an excellent example to reconsider, whether cover art has to be spectacular to be named art!
I think, there are contrary attitudes on this topic. Well, I confess, my sympathy belongs to the advocates of the compositions, which consists of more humble, but well selected graphical elements, combined to an arty cover.
Visual, as well as audible art, both are an instrument of mankind's emotional language. An essential reason to keep it well structured. One of the main preconditions to facilitate human communication.